In general, a dash panel as a sound-absorbing/blocking member is mounted at the boundary between an engine room and an indoor of a vehicle and absorbs and blocks engine noise transmitted to the indoor is mounted on the dash panel.
Accordingly, the dash pad may block, remove, and absorb noise from the engine and may prevent high or low-frequency complex energy generated in driving from being transmitted to the indoor of the vehicle.
For example, the dash pads for vehicles in the related art may have structures formed by stacking different materials having different thicknesses and weight based on the types of vehicles, as listed in the following Table 1.
TABLE 1Existing dash pad (Arrangement: Sound-absorbing layer −>ItemSound-blocking layer)1PU(85K) + PA6 film (50 g) + TPE (2.5 t) + PET (1,000 g)[or Modified cross-section fiber (1,000 g)]: Large-size carPA6 film: To bond an sound-absorbing layer and a sound-blockinglayer (functioning as an adhesive)2PU(85K) + PA6 film (50 g) + Hard PET(1,000 g): Small-sizedcar, gasoline PU(85K) + H/layer (1.5 t) + Hard PET(1,000 g):Small-sized car, diesel3PU(85K) + PA6 film (50 g) + Hard PET(800 g): RV gasolinePU(85K) + EVA(2.0 t) + Hard PET(800g): RV diesel4Soft PET + Hard PET
The dash pads listed in Table 1, as illustrated in FIG. 1, may have stacked structures of two to four layers including a sound-absorbing layer at the engine room side and a sound-blocking layer at the indoor.
Although the conventional dash pads are manufactured in the structures formed by stacking different materials in two to four layers for the types of vehicles in order to improve sound-absorbing/blocking performance, the PU material has been used for the sound-absorbing layer and the hard PET also has been used for the sound-blocking layer, and thus, the weight and manufacturing costs may generally increased to improve sound-absorbing/blocking performance for each type of vehicles.
Moreover, a start mold and a mass production mold may be required for testing performance in mass production, and further, a mold, a trimming mold, and a PU foaming mold may be used for producing actual products, such that the investment cost and manufacturing cost have increased. Further, there is a need of a film (PA6) for bonding the sound-absorbing layer and the sound-blocking layer, and thus the manufacturing cost and the number of process may increase.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may include information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.